Minecart command block teleport issue

Hello.

I'd really like some help on this little issue that I'm having with when I try to teleport a minecart to another area.

I have a track and at the end of the track I have a detector rail connected to a command block with the teleport command set up to teleport me into a 10x10 or so square about 20 blocks away. Whenever I get into the minecart and come close to the detector rail it bugs out. It sort of teleports me very quickly but in a short moment I'm back where I was.

Any help on this? Thanks guys.

'Lord Sargeras, sweep your molten fist through this world, so that it may be reborn in flames and darkness!''So the light's vaunted justice has finally arrived.''Boldly said. But I remain...unconvinced.'My Warrior